Domestic electric furnace



June 10, 1952 Q AYRES ET AL 2,600,044

DOMESTIC ELECTRIC FURNACE Filed March 18, 1949 2 SHEETS-SHEET 1 /5 FChar/e5 L/gye/J W M//arc//V. ur/d EN OR ATTORNEY J1me 1952 c. L. AYRESEIAL DOMESTIC ELECTRIC FURNACE 2 SHEETSSHEET 2 Filed March 18, 1949 w uo w M 3 l h 4A0, 1 4 :T I 9 I/ 2 II F 3 4 0 O M @n I O Q W 1 H H m C O Om INVENTOR B ll ATTORNEY Patented June 10, 1952 OFFICE DOMESTIC ELECTRICFURNACE Charles L. Ayers, Puyallup, and Willard M. Murray, Bellingham,Wash.

Application March 18, 1949, Serial No. 82,222

(Cl. hil -39) Claims.

This invention relates to the electric heating of residences and otherstructures and has special reference to such furnaces as supply theresidence with heated air.

The objects of our invention are, first, to provide such a furnace aswill be safe to use in comparison to electric heaters of other types;second, which is acceptable in its design and construction to The FireUnderwriters Laboratory, Inc.; third, which will supply an abundantvolume of fresh, clean, and uniformly warmed air to the residence;fourth, in which the air is filtered before it is heated, to remove anyfree dust particles therefrom; fifth, in which the heat is stored whennot in operation; sixth, which has an exceptionally high efficiencyrating and in which the loss of heat units (B. t. u.) is extremely low;and seventh, which, though providing heated air to the residence, isitself cool and may be touched with the bare hands without discomfort.

We attain these and other objects as will readily be apparent to thoseskilled in the art, by the devices, mechanisms and arrangementsillustrated in the accompanying drawings, in which: Fig. 1 is a frontelevation of our improved electric furnace; Fig. 2 is a vertical sectionthereof; Fig. 3 is a cross section thereof, taken on the line 33 in Fig.2; Fig. 4 is an elevation of the heating unit panel; Fig. 5 is a crosssection of one of the heating units; and Fig. 6 is a diagram of theelectric wiring.

Identical numerals of reference refer to the same parts throughout theseveral views.

This electric furnace is composed of a plurality of nested platesdividing it into vertical passages in which the air being heated iscaused to flow in such manner that the exposed outside plates are alwayscool to the touch. As seen in Fig. 1 it is a tall relatively narrowstructure which is intended to be erected in contact with or close toone of the partition walls of the house being heated.

As seen in Fig. 3, the outer shell is composed of a vertical box [0,having a front closure panel H, the two parts being connected togetherby lock joint as illustrated, and with suitable bolts passingtherethrough. The front panel 1! is provided with a removable section [2at the base whereby access may be had to the two thermostats and to theair filter l3 located inside the structure, and this section l2 may, ifdesired, be provided with a suitable louvre inlet l4 adapted to admitair to the interior of the heater and under the said filter l3. Air alsomay be admitted into the interior of the heater by a suitable inlet ductI5, if desired.

The front panel II is also provided with an upper section I6 hinged atI! to the upper closure of the box I0.

The rear wall of the outer box It is provided with two outlet openings,the lower opening 18 being located above the said filter l3, and theupper opening l9 being positioned at the upperthe heater, and thechannel 2! conveying the heated air from the bottom to the top.

This inner structure comprises a container 22. whlch forms a rectangularbox, similar in form;

to the outer box l0 and having a closure plate 23, and is secured to theouter shell 10 by suitable bolts 24 (Fig. 3). tainer 22 is curvedrearward and extends to the lower heat outlet opening I8. The upperendof the inner structure 22 is provided with an electric fan 26 adaptedto draw cold air from the chamber 20, through the opening 21 in the wall22 and to drive the air downward in the interior of the container 22.The closure plate 23 extends down from the top of the container 22 to apoint slighty above the curved end 25.

A balanced valve plate 28 is mounted on hori zontal pivots slightlybelow the fan outlet, said plate 28 being overbalanced to open thepassage when the fan is in operation. When the fan is not in operationthe valve plate 28 closes the upper end of the box 22 and retains heatin the interior of the container 22 and prevents the fan and its motorfrom becoming overheated.

The heating panel is illustrated in Figs. 2-5,

and is mounted within the inner structure 22 and comprises a supportingplate 29 suitably secured in vertical position in spaced relation toThree bridge.

the walls of the container 22. bars 30, 3| and 32 are secured,respectively, at the upper, central and lower portions of the said plate29. secured to the said bridge bars.

Each of these heating units consists of a metal container havingelectric wires 35, completely surrounded by a suitable insulationmaterial 36,; therein and closed by a plate 31. r The wires 35-- aresuitably led to insulated terminals 38 extending out from the container34 at each end of the heating units.

The insulated terminals 38 of said heating The lower end 25-of the con Aplurality of heating units 34 are units are respectively connected tothree bus bars 39, 40 and 4|, located respectively at the top, centerand lower ends of the plate 29. These bus bars are insulated by sheetsof mica from the heating units 34 but are connected to the terminals 38thereof. The supporting plate 29 and all the elements of the heatingunit are enclosed in the container 22 by the closure plate 42. As abovedescribed, the container 22 is open at its lower end, and its upper endis open to the flow of air from the fan 26, except that such.

opening is closed by the plate 28 when the fan is not in operation, toretain the heat in the container and to protect the fan motor from beingpreheated. The air from the fan contacts the heating elements and theheated air passes from the container out of the furnace by the outletsl8 and 19.

All parts of the heating element are surrounded by flowing air which isbeing driven downward therepast by the fan 25. This air is cool freshair from the outer channel 23 and keeps all the surfaces of the plates22, 29, 42 and 23 relatively cool, and picks up heat as it contacts theheating units 34.

The wiring of our improved electric furnace is illustrated in Fig. 6.The wires 43 and 44 are the live wires of the electric service linewhich energizes this furnace, and the wire 45 is the neutral line, therebeing a potential of H volts between the wire 45 and either of the wires43 or, while'there is a potential of 220 volts on the circuit composedof the wires 43 and 44.

A double pole magnetic switch 46 controls the main heating circuit whichis composed of the 1 wires 41 and 48 leading from the poles of theswitch to the bus bars; the wire 41 leads to the bus bars 39 and 4 I,while the wire 48 leads to the bus bar 40, so that when the switch 46 isclosed the current flows by the wires 41 and 48 through all the heatingwires 35, generating the heat utilized by the furnace. The magneticswitch 46 is closed by means of the electromagnet wire 49 which isenergized from the main line wire 43 through the connecting wire 50.leads therefrom through two thermostats 52 and 53 adapted, respectivelyto open when the temperatures reach 250 and 300. The thermostat 52 isplaced so as to protect the fan motor 26 from getting overheated, andthe thermotat 53 is to place an upper limit on the heat developed in thefurnace. The wire 5! then passes through the manual master switch 54 andthe room thermostat 55, which is open if the room temperature exceedsthe selected level and is closed when it falls below that level. Theline 5! then passes to the other main line wire 44. Thus the thermostatsare in the 220 volt line.

A spring 56 opens the switch when the line 5| is broken by the openingof the switch 54 or any of the thermostats 52, 53 or and thus cuts offthe current from the heating units 34.

A pilot light 5'! is mounted in a. circuit 58 leading from theswitch-controlled main line 41 to the neutral wire 45 and is thereforeenergized when the switch 45 is closed and the ftu'nace is being heated.

The electric fan 26 is also energized on the volt circuit 59,independent of whether the switch 48 is open or closed. This circuitleaves the above circuit 58, passes through the fan motor 26 and througha thermostat 6D and thence to the main line wire 43. The purpose of theheat-closed thermostat 50 is to delay the oper- The wire 4 ation of thefan until the heating units have attained a sufficient heat, otherwisethe fan would start blowing cold air into the rooms and the heating ofthe house would be delayed. When the heating unit has reached apreferred temperature, the thermostat 6D closes and the fan thensupplies cool air to the heating units to be heated and delivered asabove described. In the summertime the fan 26 may be used to supply astream of cool air to the house by closing the manual control switch GIwhich is placed in the shunt line 62 around the said thermostat 60.

Thus it will be seen that the operation of this furnace is safeguardedagainst attaining too high a degree of temperature by the thermostats 52and 53; against overheating the fan by the thermostat 52, and againstsupplying cold air before the furnace has reached a sufficient degree ofheat by the thermostat 60. It will also be seen that the plates Ill andH forming the outer surfaces of the furnace are swept by cool air onboth sides and are therefore kept cool.

The materials used in the construction of the furnace are preferably:the heating units are each of 500 watts at 220 volts and arecommercially known as Westinghouse Heating Units; the sheet metal usedis preferably 18 gauge aluminum; and the switches, thermostats and otherstandard parts are all commercial articles of suitable capacity atpresent found on the open market.

Having described our improved electric furnace, what we claim and desireto secure by Letters Patent, is:

1. An electric furnace comprising an outer rectangular container; aninner container mounted in said outer container and secured thereto inspaced relation, thereby dividing said outer container into two passageseach said passage extending vertically the length of said innercontainer, and separated from each other by said inner container, thefirst said passage being adapted to receive cool air at its base, andthe second said passage having open connection with the lower end ofsaid inner container; an activated fan in said inner container anddrawing cool air from the top of the first said passage and dischargingit downward into the top end of said inner container; heating elementsmounted in said inner container in spaced relation thereto and adaptedto heat the air discharged by said fan; and a hot air outlet from thesecond said passage at a point remote from said fan.

2. An electric furnace as set forth in claim 1, wherein said actuatedfan is positioned at the upper end of said inner container anddischarges the air downward in said inner container and past the heatingelements therein; together with a, balanced plate-valve positionedbetween said fan and said heating elements, whereby when said fan is inoperation the discharge therefrom is free, and when said fan is inactivethe upper end of said inner container is closed against the escape ofheat past said fan.

3. A furnace comprising a container compartmented to form two outervertical passages separated by an inner vertical passage, the innerpassage communicating at its upper end with the first outer passage andat its lower end with the second outer passage, heater means mounted inthe inner passage, fan means for drawing air from the first outerpassage downward past the heater means, cool air inlet meanscommunicating with the first outer passage adjacent its lower 5 end, andhot air outlet means communicating with the second outer passage.

4. An electric furnace comprising a container compartmented to form twoouter vertical passages separated by an inner vertical passage, theinner passage communicating at its upper end with the first outerpassage and at its lower end with the second outer passage. electricheater means mounted in the inner passage, fan means for drawing airfrom the first outer passage downward past the heater means, cool airinlet means communicating with the first outer passage adjacent itslower end, and hot air outlet means communicating with the second outerpassage.

5. The furnace of claim 3 including'a plate valve in the inner passagearranged between the heater means and Ian means and opened uponactivation or said tan means.

CHARLES L. AYERS. WILLARD M. MURRAY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

